1. Field of the Invention
The present invention relates to ink jet recording apparatus and more particularly to a multi-nozzle ink jet recording apparatus wherein a picture or a character responsive to information signals is recorded on a recording medium through the use of ink droplets ejected from a plurality of nozzles.
2. Description of the Prior Art
Various types of ink jet recording apparatus have been proposed and practised wherein ink droplets are ejected from nozzles to record information on a recording medium.
One of them is of a generally called charge modulation type. In this type, an electrical energy-mechanical energy converting element (electrostrictive vibrator) is mounted on a nozzle head fed with ink and a high frequency voltage is applied to the element to vibrate the nozzle head so that the vibration generates ink droplets from the tip of the nozzle with the period of vibration. Simultaneously, the ink droplets are charged by information signals in synchronism with the generation of the ink droplets. The thus charged ink droplets are then deflected in accordance with their charges and recorded on a recording medium. Another is of the on-demand type as disclosed in U.S. Pat. No. 3,946,398, for example, which comprises ink chambers fed with ink, electrostrictive vibrators (PZT) provided for the ink chambers and a nozzle head provided with nozzle apertures in communication with the ink chambers for ejection of ink droplets, whereby the interior volume of the ink chamber is varied by an information signal applied to the electrostrictive vibrator to cause ink in the ink chamber to be ejected from the nozzle aperture in the form of a single ink droplet in response to the information signal, thereby recording desired information on a recording medium.
The printing speed of the latter type is inferior to that of the charge modulation type because the information signal is applied only when recording of the ink droplet is desired and the single ink droplet is ejected from the nozzle aperture of the nozzle head in response to the single information signal. This on-demand type ink jet recording apparatus is, however, advantageous in that the nozzle head itself is simplified and recovery of surplus ink droplets and deflection of the ink droplets are unnecessary, which results in miniaturization of the apparatus as a whole, and for these reasons, it has been highlighted as a compact type ink jet recording apparatus.
In practising the ink jet recording apparatus of on-demand type, it is general to arrange a plurality of ink chambers in parallel in the single nozzle head and to drive the respective ink chambers independently.
With this construction, however, upon simultaneous energization of electrostrictive vibrators associated with, for example, two adjoining ink chambers, the pressures of these electrostrictive vibrators are imparted to other chambers adjacent to the two ink chambers which are not scheduled to be energized with a result that so-called interference phenomenon is caused wherein minute ink droplets are generated from nozzle apertures which are in communication with those ink chambers which are not expected to participate in the generation of the ink droplets. Consequently, quality of pictures recorded on the recording medium is degraded.